Method and system embodiments for converting ethanol to para-xylene and ortho-xylene
Inventors
Ramasamy, Karthikeyan K. • Guo, Mond • Rosin, Richard Russell • KOCAL, JOSEPH ANTHONY
Assignees
Lanza Tech Inc • Battelle Memorial Institute Inc • Lanzatech Inc
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Publication Number
US-12264116-B2
Publication Date
2025-04-01
Expiration Date
Abstract
Disclosed herein are embodiments of a method and system for converting ethanol to para-xylene. The method also provides a pathway to produce terephthalic acid from biomass-based feedstocks. In some embodiments, the disclosed method produces p-xylene with high selectivity over other aromatics typically produced in the conversion of ethanol to xylenes, such as m-xylene, ethyl benzene, benzene, toluene, and the like. And, in some embodiments, the method facilitates the ability to use ortho/para mixtures of methylbenzyaldehyde for preparing ortho/para xylene product mixtures that are amendable to fractionation to separate the para- and ortho-xylene products thereby providing a pure feedstock of para-xylene that can be used to form terephthalic anhydride and a pure feedstock of ortho-xylene that can be used for other purposes, such as phthalic anhydride.
Core Innovation
The invention provides a catalytic, multi-zone conversion of an ethanol-containing feed stream to polymer-grade p-xylene and o-xylene, starting from ethanol generated by converting syngas via gas fermentation. At least one article is gasified to produce syngas, and the syngas is converted by gas fermentation to generate a stream comprising ethanol. The ethanol-containing stream is then contacted with an oxidation catalyst under oxidation conditions to form an oxidation zone effluent stream comprising acetaldehyde.
The oxidation zone effluent stream is passed to a dimerization zone and contacted with a dimerization catalyst under dimerization conditions to produce a dimerization zone effluent stream comprising 2-butenal. The dimerization zone effluent stream is passed to a cyclization zone and contacted with a cyclization catalyst under cyclization conditions to form a cyclization zone effluent stream comprising o-methylbenzaldehyde and/or p-methylbenzaldehyde. The cyclization zone effluent stream is then passed to a hydrogenation zone and contacted with a hydrogenation catalyst comprising a first Group VIII metal deposited on a support material.
The hydrogenation zone effluent comprises a non-equilibrium mixture of o-xylene, p-xylene, and m-xylene, including a constrained m-xylene content relative to an m-xylene equilibrium concentration in dependent claims. At least a portion of the p-xylene from the non-equilibrium mixture is passed to a first reaction zone under first reaction conditions to produce a stream comprising terephthalic acid, and the terephthalic acid is passed to a second reaction zone under second reaction conditions to produce a stream comprising polyethylene terephthalate. The polyethylene terephthalate is used to generate a new article, and dependent claims further refine the process using specified hydrogenation catalyst/support compositions and optionally include separation and recycling steps to reach predetermined target concentrations.
Claims Coverage
The independent claim defines an integrated, sequential multi-zone method from syngas-derived ethanol to non-equilibrium xylenes and further to terephthalic acid and polyethylene terephthalate used to generate a new article. Dependent claims refine hydrogenation catalyst/support composition, specify support material selections, impose quantitative constraints on m-xylene in the non-equilibrium xylene mixture, and optionally add separation and recycling steps with predetermined target concentrations.
Syngas-to-ethanol feed generation by gasification and gas fermentation
Providing a stream comprising ethanol by subjecting at least one article to gasification to produce syngas and converting the syngas by gas fermentation to generate the stream comprising ethanol.
Sequential oxidation, dimerization, and cyclization to methylbenzaldehydes
Contacting the feed stream comprising ethanol with an oxidation catalyst under oxidation conditions to form an oxidation zone effluent stream comprising acetaldehyde; passing the oxidation zone effluent stream to a dimerization zone and contacting the oxidation zone effluent stream with a dimerization catalyst under dimerization conditions to produce a dimerization zone effluent stream comprising 2-butenal; passing the dimerization zone effluent stream to a cyclization zone and contacting the dimerization zone effluent stream with a cyclization catalyst under cyclization conditions to form a cyclization zone effluent stream comprising o-methylbenzaldehyde and/or p-methylbenzaldehyde.
Hydrogenation to a non-equilibrium xylene mixture
Passing the cyclization zone effluent stream to a hydrogenation zone and contacting the cyclization zone effluent stream with a hydrogenation catalyst comprising a first Group VIII metal deposited on a support material to produce a hydrogenation zone effluent comprising a non-equilibrium mixture of o-xylene, p-xylene, and m-xylene.
Conversion of p-xylene to terephthalic acid and then polyethylene terephthalate
Passing at least a portion of the p-xylene from the non-equilibrium mixture to a first reaction zone under first reaction conditions to produce a stream comprising terephthalic acid; passing the stream comprising terephthalic acid to a second reaction zone under second reaction conditions to produce a stream comprising polyethylene terephthalate.
Use of polyethylene terephthalate to generate a new article
Using the polyethylene terephthalate from the stream comprising polyethylene terephthalate to generate a new article.
Hydrogenation catalyst composition with palladium and rhenium on carbon
The hydrogenation catalyst whose support material is carbon, with palladium as the first Group VIII metal and rhenium as the modifier component.
Selectable support materials for the hydrogenation catalyst
The support material is chosen from the listed materials including any combination thereof.
Quantitative constraint on m-xylene relative to m-xylene equilibrium concentration
The non-equilibrium mixture of xylenes contains m-xylene in an amount from 0 wt% to less than 40 wt% of an m-xylene equilibrium concentration.
Tighter quantitative constraint on m-xylene relative to m-xylene equilibrium concentration
The non-equilibrium xylene mixture in which m-xylene is present at 0 wt% to 5 wt% of the m-xylene equilibrium concentration.
Separation and recycling to predetermined target concentrations
Including separation and/or recycling steps in which effluent from an oxidation zone, dimerization zone, cyclization zone, and/or hydrogenation zone is recycled back to its respective zone until specified target concentrations of acetaldehyde, 2-butenal, o-methylbenzaldehyde and/or p-methylbenzaldehyde, and/or xylenes are achieved, including combinations of these recycling steps.
Across the independent claim and refinements shown in the provided claim excerpts, the method is centered on sequential catalytic conversion from syngas-derived ethanol through oxidation, dimerization, and cyclization to methylbenzaldehydes, followed by hydrogenation using a Group VIII metal catalyst on a support to produce a non-equilibrium xylene mixture. The non-equilibrium mixture is then used to form terephthalic acid and polyethylene terephthalate, which is used to generate a new article, with dependent claims further specifying catalyst/support details, constraining m-xylene content, and optionally using separation/recycling to predetermined target concentrations.
Stated Advantages
Documented Applications
Using polyethylene terephthalate from the stream comprising polyethylene terephthalate to generate a new article.
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